7. You deserved it


#1


Your bill is NaN.


function StaffMember(name,discountPercent){
    this.name = name;
    this.discountPercent = discountPercent;
}

var sally = new StaffMember("Sally",5);
var bob = new StaffMember("Bob",10);

// Create yourself again as 'me' with a staff discount of 20%
var me = new Object("Alex",20)

var cashRegister = {
    total:0,
    lastTransactionAmount: 0,
    add: function(itemCost){
        this.total += (itemCost || 0);
        this.lastTransactionAmount = itemCost;
    },
    scan: function(item,quantity){
        switch (item){
        case "eggs": this.add(0.98 * quantity); break;
        case "milk": this.add(1.23 * quantity); break;
        case "magazine": this.add(4.99 * quantity); break;
        case "chocolate": this.add(0.45 * quantity); break;
        }
        return true;
    },
    voidLastTransaction : function(){
        this.total -= this.lastTransactionAmount;
        this.lastTransactionAmount = 0;
    },
    // Create a new method applyStaffDiscount here
    applyStaffDiscount: function(employee) {
        this.total -= this.total * (employee.discountPercent / 100);
    }
    
};

cashRegister.scan('eggs',1);
cashRegister.scan('milk',1);
cashRegister.scan('magazine',3);
// Apply your staff discount by passing the 'me' object 
// to applyStaffDiscount
cashRegister.applyStaffDiscount(me);

// Show the total bill
console.log('Your bill is '+cashRegister.total.toFixed(2));


#2

In the above statement, me is {}. Object() only takes two possible arguments, no argument or an object literal.

var me = new Object({name: "Alex", discountPercent: 20});

However, it is still not a member of the StaffMember class. To make it inherit from that class, we would need to add it to the prototype of our instance:

me.prototype = new StaffMember;

Seems a little bit much considering we could just declare it all in one go, as the examples above show:

var me = new StaffMember("Alex", 20);

Edit:

Clearly I was only speculating in the above. Testing proves me wrong.

=> { name: undefined, discountPercent: undefined }

#3

The code worked,I didn't realise i put "Object" instead of StaffMember, thanks


#4

Just finding the error of my ways:

function StaffMember(name,discountPercent){
    this.name = name;
    this.discountPercent = discountPercent;
}

var me = new Object({name: "Alex", discountPercent: 20});

me.prototype = StaffMember;

console.log(me);

// { name: 'Alex', discountPercent: 20, prototype: [Function: StaffMember] }

And,

me.prototype = StaffMember.prototype;

console.log(me);

// { name: 'Alex', discountPercent: 20, prototype: {} }

#5

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